In recent years, there have been proposed various types of contactless power transfer systems that transfer electric power in a contactless manner between a power reception device provided in a vehicle and a power transmission device provided outside the vehicle (PTLs 1 to 7).
In the aforementioned contactless power transfer system, alignment between the power reception device and the power transmission device is required. For example, Japanese Patent Laying-Open No. 2012-80770 (PTL 1) discloses a vehicle in which parking support is performed by using a power reception unit that receives, in a contactless manner, electric power output from a power transmission device provided outside the vehicle. This vehicle includes: a rectifier for rectifying AC power received by a secondary self-resonant coil (power reception coil) of the power reception unit; a resistance for detecting a distance and a relay that are provided between a pair of power lines on the output side of the rectifier and are serially connected; and a voltage sensor for detecting a voltage generated at the resistance for detecting the distance. When parking support is performed, weak electric power is output from a power transmission coil of a power transmission unit and the aforementioned relay is turned on. Thus, parking support is performed by using the voltage detected by the voltage sensor (refer to PTL 1).